The effects of intraoperative radiotherapy on bone-healing ability in relation to different doses and postradiotherapy intervals.

Abstract

Alterations in bone-healing ability after intraoperative radiotherapy were investigated in relation to different doses and postradiotherapy intervals in an experimental model. Bilateral osteotomy of the fibulae of 56 rabbits was carried out either immediately, 13 weeks or 39 weeks after unilateral intraoperative radiotherapy with 10-MV X ray using one of three doses, 25, 50, or 100 Gy. The healing of the fibulae was evaluated radiographically and histologically 13 weeks after the osteotomy. Bone-healing ability was irreversibly reduced in all irradiated fibulae and these damages occurred in a dose-dependent manner. The severity of the damage also tended to increase with the time interval between irradiation and osteotomy. This interval-related aggravation was characterized by augmented bone loss at the osteotomy ends and atrophy of the neighboring areas. These results serve as useful information concerning the surgical intervention of irradiated bone during and after intraoperative radiotherapy, and also after conventional radiotherapy.